Polycell Stain Stop Aerosol 250ml

In-Depth Look

Stain bleed-through is a common decorating problem. You paint over a water stain on the ceiling, it looks fine while wet, and then the brown mark comes back as the paint dries. Polycell Stain Stop Aerosol is made to stop this.

How Stain Blocking Works

Some stains dissolve into fresh water-based paint and come back through to the surface as it dries. A stain blocker puts a barrier coat over the mark first, so the stain stays under the paint instead of coming through.

Using the Aerosol

The spray format suits small, single stains. Instead of opening a tin of primer and cleaning brushes afterwards, you shake the can and spray onto the stain. Check the can for drying time and the surfaces it suits, then overcoat with emulsion or gloss.

Summary

Polycell Stain Stop Aerosol is for spot treating stains rather than priming whole walls. For a single water mark on a ceiling it is quick to use. For larger stained areas, a tin of stain-blocking primer such as Zinsser Bulls Eye 1-2-3 suits the job better.

How It Compares

Polycell Stain Stop comes in a 250ml aerosol. The maker says it blocks water stains, grease, nicotine, soot, crayon and rust. It is designed to give one coat coverage over existing stains. For stubborn stains a second coat may be needed, applied once the first is fully dry.

Stains show through emulsion because marks from water, smoke or grease can be carried through thin paint. A stain blocker sits between the mark and the topcoat.

For a brush-on alternative on this site, see the Zinsser Bulls Eye 1-2-3 primer. The Mangers sugar soap powder is used for cleaning surfaces before painting. Our guide on painting a room covers the rest of the job.

Common Questions

Why do ceiling stains come back through paint? Marks from water, smoke or grease are carried through thin paint, so a stain can reappear after repainting. A stain blocker is applied first so that the topcoat has a sealed surface to sit on.

Do I need to fix the cause first? Yes. Deal with the leak or source of the stain and let the area dry before you treat it. A blocker does not stop new water getting in.

How do I use an aerosol stain blocker? Shake the can, then spray from about 20 to 30cm, as the maker instructs. Keep the coats light and even, and ventilate the room. For a stubborn stain, apply a second coat once the first is fully dry.

What can I paint over it? Follow the label. If you are overcoating with solvent-based paint, the maker says to prime the treated area with water-based paint first.

Keep the can away from heat and flames, and follow the instructions on the can.